1. Field of the Invention
The present invention relates to an ink jet recording apparatus and an abnormality detection method of an ejector, and particularly relates to a technique for detecting an abnormality of an ejector in an ink jet head having a plurality of ejectors.
2. Description of the Related Art
An ink jet head which is used in a recording head of an ink jet recording apparatus has a plurality of ejectors as an ejection mechanism that ejects droplets. Regarding techniques for detecting an abnormality of an ejector in a recording head, techniques disclosed in JP1988-260448 (JP-563-260448) and JP2012-232542 are known.
JP1988-260448 (JP-S63-260448) discloses a technique in which, in an ink jet printer, an image printed during a print job is read by an image sensor, and a jet error of a jet nozzle of a recording head is detected by comparing printed dots with printing data for comparison. The terms “ink jet printer”, “image sensor”, “printing data”, “recording head”, “jet nozzle”, and “jet error” disclosed in JP1988-260448 (JP-S63-260448) can be comprehended as the terms corresponding to “ink jet recording apparatus”, “image reading unit”, “print data”, “ink jet head”, “nozzle”, and “ejection abnormality”, respectively.
JP2012-232542 discloses a method of implementing ejection inspection with an appropriate detection sensitivity by changing an allowable upper limit of the number of detections of a non-ejecting nozzle within a corresponding ejection head which serves as a determination criterion when “defective ejection” of an ejection head is determined, in accordance with a printing resolution or the type of printing data. The terms “ejection head” and “non-ejecting nozzle” disclosed in JP2012-232542 can be comprehended as the terms corresponding to “ink jet head” and “non-ejecting nozzle”, respectively.